1998 s70 misfire cyl3 only on high load

sk55 · Post by **sk55** » 23 Aug 2015, 19:33

hi guys,

i just got my first 98 s70 T5... i am getting a P0303 code.. which cyl 3 misfire. seem to only happen
when driving WOT under high load like going up a hill. normal driving, doesn't throw the code, engine feels okay.

i changed the plugs... used volvo plug... still getting the code?

whats the next step should i change the wires?

or check distributor cap.

thanks

des

Post by **abscate** » 23 Aug 2015, 19:36

Cap rotor wires

Compression test on cylinder 3

Did you gap the new plug to 0.028 inches?

Post by **Ozark Lee** » 23 Aug 2015, 19:37

sk55 wrote:
whats the next step should i change the wires?

or check distributor cap.

Yes.

At least check the ignition wire date codes and do a visual on the cap and rotor.

It could also be an injector that is getting dirty. You can listen to the injectors with a screwdriver and when they start to clog they will sound "duller" than the others.

If all of that checks OK then do a compression test. It could be a valve starting to burn.

...Lee

Post by **E Showell** » 25 Aug 2015, 19:55

99% it is a burned exhaust valve. I'd expect significantly lower compression on #3 than the others. That's what sent my first engine to a viking funeral.